Patent GB-820120-A (GB)
Title: Process for modifying the structure and properties of addition polymers
IPC: C08F2/54
Filed: 1956-04-06
Abstract: The properties of addition polymers are changed by subjecting the polymer to ionising radiation while it is in intimate contact with at least one organic compound, which chemically bonds (as such or in the form of a polymeric structure) with the addition polymer.  The modifier which may be dispersed, diffused or coated upon the polymer is preferably kept in an inert atmosphere or is enclosed by a polyethylene film, aluminium foil or other material which is impervious to air and water while it is being irradiated. Additionally it may be in contact with a compound having protective or anti-oxidant effects with respect to the polymer or the modifier or both and during the irradiation temperature is preferably kept between 0 DEG  and 75 DEG  C., if necessary by cooling. The process is preferably carried out in the presence of calcium tungstate, zinc sulphate, metallic lead or other radiation transfer agent capable of absorbing radiation and re-admitting it in a lower form of energy. Examples of radiation dosages are given.  Organic modifiers for use in the invention may be found among all classes of organic compounds, and may contain, besides carbon, one or more of the elements hydrogen, halogen, nitrogen, oxygen, or sulphur.  (Those organic compounds, the bonds of which are easily broken, as for instance chain transfer agents, are preferred.) They may be of low or of high molecular weight, especially of polymeric structure.  Thus there may be used Alcohols, such as methanol, ethanol, laurol; Glycols, such as glycerol, pentaerythritol, sorbitol, mannitol and partial esters of these polyols; Ethers, such as dimethyl, diethyl and ethylmethyl ethers, glycol ethers; Oxyalkylated ethers of partial esters of the polyols, such as the polyoxyethylene derivatives of fatty acid partial esters of sorbitol; Polyethers, such as polyoxyethylene glycol; Mercaptans, disulphides and thioethers analogous to the above; Amines, such as methylamine, ethylamine, hexamethylene diamine and dodecylamine; Amides of these amines formed with acids, such as formic acid, adipic acid, suberic acid and stearic acid; organic halides, such as chloromethane, chloroform, carbon tetrachloride, chloroethane, and dichlorodifluoromethane, chloroethylene and dodecafluoroheptyl alcohol.  The modifier may be an unsaturated compound, particularly one which may be employed to form addition polymers by vinyl polymerization, e.g. styrene, the acrylic acid esters, vinyl chloride, vinylidene chloride, vinyl acetate, the vinyl ketones, the vinyl ethers, such as divinyl ether, acrylonitrile, methacrylonitrile, methoxydodecamethyleneoxy methacrylate, 1,3-butadiene, isoprene, chloroprene, 2,3-dimethyl-1,3-butadiene, ethylene, propylene, the acetylenes for instance phenylacetylene, the allyl esters, vinyl compounds (other than those already mentioned) containing halogen, sulphur, nitrogen or phosphorus, and the vinyl silanes.  Polymers prepared from such of the above monomeric materials as are polymerizable are also suitable.  The modifiers may be incorporated with the polymer before shaping, or they may be applied to the shaped articles, e.g. as solutions or in suitable cases as pure compounds, for instance by spraying, calendering, immersion, padding, or exposure to vapour condensation.  In suitable cases a solution of the modifier may be applied to the surface of a shaped article and the solvent flashed off before the irradiation. If desired excess liquid may be removed before irradiation by squeezing.  Synthetic addition polymers treated in accordance with the invention are primarily those formed by vinyl polymerization from alkylenically unsaturated monomers, such as styrene, the acrylic acid esters, vinyl halides, vinylidene halides, vinyl esters, ketones and ethers, vinyl compounds containing sulphur, nitrogen or phosphorus and other vinyl compounds containing halogen, vinyl silanes, ethylene, propylene, allyl ethers, acrylonitrile, methacrylonitrile, 1,3-butadiene, isoprene, chloroprene, and 2,3-dimethyl-1,3-butadiene. The polymers treated may be in the form of funicular-shaped structures such as filaments, staple fibres, and yarns comprising them; to woven, knitted, felted or fused fabrics and to their films. Shaped structures to be treated may be made by extrusion, moulding, casting or calendering.  The polymers may also be treated in the form of finely comminuted particles which may subsequently be shaped, either in the molten state or in solution, e.g. by extrusion, moulding or casting.  In addition to the above other modifications would be useful in other substrates, for example in films, which may be modified to improve adhesion to various coating or laminating agents, to change "slip" or the ease with which one film slides over another, to affect oil resistance or permeability (e.g. of synthetic elastomers), to produce non-reflective or decorative coatings on film or sheet, to improve the ease of printing colours on a sheet &c. Specific shaped articles which may be treated include woven or knitted fabrics, articles made from them for clothing or industrial use, reinforcement for composite structures (such as cords for mechanical rubber goods and fibre for laminates), artificial bristles or artificial straw and rods, bars, sheets, plates and laminates. Those properties which are not primarily a function of surface characteristics (e.g. tenacity, elongation, modulus, and the like) in some cases may be more conveniently modified by incorporating modifiers in the polymeric matrix and then subjecting it to particle irradiation.  It may be desirable to incorporate one or more modifiers in the matrix and coat one or more modifiers on the surface of the polymer.  Specifications 758,735 and 798,340 are referred to.ALSO:The properties of addition polymers are changed by subjecting the polymer to ionizing radiation while it is in intimate contact with at least one organic compound, which chemically bonds (as such or in the form of a polymeric structure) with the addition polymer. The modifier which may be dispersed, diffused or coated upon the polymer is preferably kept in an inert atmosphere or is enclosed by a polyethylene film, aluminium foil or other material which is impervious to air and water while it is being irradiated. Additionally, it may be in contact with a compound having protective or antioxidant effects with respect to the polymer or the modifier or both and during the irradiation temperature is preferably kept between 0 DEG  and 75 DEG  C., if necessary by cooling. The process is preferably carried out in the presence of calcium tungstate, zinc sulphate, metallic lead or other radiation transfer agent capable of absorbing radiation and re-admitting it in a lower form of energy. Examples of radiation dosages are given.  Organic modifiers for use in the invention may be found among all classes of organic compounds, and may contain, besides carbon, one or more of the elements hydrogen, halogen, nitrogen, oxygen or sulphur.  (Those organic compounds, the bonds of which are easily broken, as for instance chain transfer agents, are particularly preferred.)  They may be of low molecular weight or of high molecular weight, especially of polymeric structure.  Thus there may be used alcohols, such as methanol, ethanol, laurol; glycols, glycerol, pentaerythritol, sorbitol, mannitol and partial esters of these polyols; ethers, such as dimethyl, diethyl and ethylmethyl ethers, glycol ethers; oxyalkylated ethers of partial esters of the polyols, such as the polyoxyethylene derivatives of fatty acid partial esters of sorbitol; polyethers, such as polyoxyethylene glycol; mercaptans, disulphides and thioethers analogous to the above; amines, such as methylamine, ethylamine, hexamethylene diamine and dodecylamine; amides of these amines formed with acids, such as formic acid, adipic acid, suberic acid and stearic acid; organic halides, such as chloromethane, chloroform, carbon tetrachloride, chloroethane, and dichlorodifluoromethane, chloroethylene and dodecafluoroheptyl alcohol.  The modifier may be an unsaturated compound, particularly one which may be employed to form addition polymers by vinyl polymerization, e.g. styrene, the acrylic acid esters, vinyl chloride, vinylidene chloride, vinyl acetate, the vinyl ketones, the vinyl ethers, such as divinyl ether, acrylonitrile, methacrylonitrile, methoxydodecamethyleneoxy methacrylate, 1,3-butadiene, isoprene, chloroprene, 2,3-dimethyl-1,3-butadiene, ethylene, propylene, the acetylenes for instance phenylacetylene, the allyl esters, vinyl compounds (other than those already mentioned) containing halogen, sulphur, nitrogen or phosphorus, and the vinyl silanes.  Polymers prepared from such of the above monomeric materials as are polymerizable are also suitable.  The modifiers may be incorporated with the polymer before shaping, or they may be applied to the shaped articles, e.g. as solutions or in suitable cases as pure compounds, for instance by spraying, calendering, immersion, padding, or exposure to vapour condensation.  In suitable cases a solution of the modifier may be applied to the surface of a shaped article and the solvent flashed off before the irradiation. If desired, excess liquid may be removed before irradiation by squeezing.  Synthetic addition polymers treated in accordance with the invention, are primarily those formed by vinyl polymerization from alkylenically unsaturated monomers, such as styrene, the acrylic acid esters, vinyl halides, vinylidene halides, vinyl esters, ketones and ethers, vinyl compounds containing sulphur, nitrogen or phosphorus and other vinyl compounds containing halogen, vinyl silanes, ethylene, propy lene, allyl ethers, acrylonitrile, methacrylonitrile, 1,3-butadiene, isoprene, chloroprene and 2,3-dimethyl-1,3-butadiene.  The polymers treated may be in the form of funicular shaped structures such as filame